THEY are tied. Of course, they are. It seems as if the Yankees and Red Sox have been deadlocked for about four years now. The Rivalry renews tonight in Fenway and it feels like Game 100 of a series with no obvious end, but with yet another poignant storyline.

Johnny Damon returns to Boston with less hair and fewer friends. A cottage industry already is rampant to speculate what kind of reception he receives on the Boggs/Clemens meter.

“It is going to be nuts,” Joe Torre said. “All of the attention is going to be on Johnny Damon.”

Torre is right, though where the focus will be is all wrong. Damon is the story of the moment. But the most important issue facing the Yankees and Red Sox is how well they are going to pitch this season.

“It is always about who pitches better,” Mike Mussina said.

Mussina’s statement came after a statement of another kind, six more ace-like innings that helped the Yankees beat the Blue Jays, 4-1. Mussina is 4-1 with a 2.31 ERA, his newly minted expertise over a changeup providing a facelift to a career that had begun to sag.

He is leading a staff that has a 3.65 ERA, which is second in the AL and a full run better than Boston’s. That is important, since the Red Sox remade themselves in the offseason from brutish Idiots to a club that wanted to revolve around pitching and defense.

So far the results for the Red Sox are mixed. Curt Schilling and Josh Beckett have starred atop the rotation, and Jonathan Papelbon has been a revelation as the closer, not yielding a run in 14 1/3 innings. However, the rebuilt set-up core has been flimsy, Julian Tavarez and Rudy Seanez in particular.

The key decision of this Boston season, though, just might involve their rotation; the choice to trade Bronson Arroyo to Cincinnati for platoon outfielder Wily Mo Pena. Arroyo was a dependable starter, fully vested in the Yankee-Red Sox confrontation. His removal hit severely at rotation depth, especially with Papelbon needed to close, David Wells talking retirement from the DL over the deteriorated state of his knee and Matt Clement’s fortitude still so uncertain.

It helps explain Boston’s love affair with Roger Clemens, and the potential for yet another Yankee-Red Sox battleground. Naturally, the Yanks will pursue The Rocket. But, currently, they are feeling comfortable about their depth. In previous seasons, with so many off-days in April, the Yanks would have rearranged their rotation to have Mussina and Randy Johnson available for Fenway. Instead, they appear confident with Chien-Ming Wang and Shawn Chacon.

Torre also seems more at ease with the length of his bullpen than at any time in recent years, and with Aaron Small being added today, that sense should expand. And, Torre says, “we feel we have something still coming in [Carl] Pavano and [Octavio] Dotel.”

Confidence in Pavano is probably misplaced, but not as misplaced as believing that Yankees vs. Red Sox now revolves around Johnny Damon. He will have the worst arm on the field when the teams play, and the determination of who wins the AL East will come down to which club has more of the best.